Wavefront aberrations, diffraction limit and scatter are three optical defects in a human eye that degrade image quality and limit ocular performance. Wavefront aberrations can be determined with a Shack-Hartmann wavefront sensor. Diffraction limit can be calculated by using e.g. Raleigh's criteria. However, scatter, and its effects on visual performance, is difficult to accurately measure.
Many modern ophthalmic techniques require an accurate assessment of ocular performance to achieve effective results. For example, many techniques rely on the ability to accurately characterize the visual performance of an eye before and after a surgical procedure. By comparing the before and after results the effectiveness of the procedure can be determined.
It can be useful to measure the optical scattering of an eye before and after an ophthalmic procedure to determine the impact on the overall visual performance of an eye. In one specific example, it can be useful to determine the scattering of an eye that occurs after the implantation of an intraocular lens (IOL).
For these and other reasons there is a continuing need for improved devices and techniques to accurately determine and quantify ocular scattering.